1. Field of the Invention
The present invention relates to guanidine-related compounds comprising a substituted tetraphenylborate ion associated with a product comprising a guanidine-related group, and to a process for obtaining such compounds, which may be employed as a means for dissolving the product in which the protection of the guanidine-related group is insured, particularly in peptide synthesis from amino acids or peptides.
2. Description of the Related Art
German patent application DOS No. 2,716,477 discloses particularly N,N',N"-substituted guanidine salts of general formula: ##STR2## in which R.sub.1, R.sub.2, R.sub.3 and R.sub.4 denote an aliphatic, cyclic, arylated aliphatic, aromatic or heterocyclic radical and in which only R.sub.1 may be a hydrogen atom.
These compounds, protonated on the carbon atom of the substituted guanidine-related group, are synthesized from a halogenated derivative of carbamic acid and from substituted thiourea and may be employed as catalysts, plant-protection agents and pharmaceutical dyes.
Furthermore, salts consisting of the tetrakis[3,5-bis(trifluoromethyl)phenyl]borate anion and certain diazonium cations such as ArN.sub.2.sup.+ and ArNHR.sub.2.sup.+ in which Ar denotes an aryl radical and R a methyl radical, are also known (Bulletin Chem. Soc. Japan, 56, 796-801, 1983, vol. 56, N.3).